Cracking sound from amp - help - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 7th August 2009, 07:17 PM   #1
Brit01 is offline Brit01  United Kingdom
diyAudio Member
 
Join Date: Jul 2008
Default Cracking sound from amp - help

Hi guys,

Getting an occasional worrying crack/pop noise coming through my amp maybe once or twice an evening. Just on left channel.

It's a 1992 Carver TFM-55. One of the rails has been replaced with new power transistors (before I bought it).

Since then I've replaced most of the power caps, some differential transistors and some resistors.
Sounds very good with the new parts but bit worried now.

Maybe a sign of one of a power transistor going?
Or maybe an old mylar cap going?

Or some old Carbon Comp. resistors?
  Reply With Quote
Old 8th August 2009, 03:47 AM   #2
diyAudio Member
 
Jan Dupont's Avatar
 
Join Date: Apr 2003
Location: Copenhagen, Denmark
Send a message via MSN to Jan Dupont
Or a bad solder
__________________
Free Schematic and Service Manual downloads www.audio-circuit.dk, Company: www.dupont-audio.com, Joint venture: www.DupontMantra.com
  Reply With Quote
Old 8th August 2009, 04:07 AM   #3
diyAudio Member
 
keantoken's Avatar
 
Join Date: Aug 2006
Location: Texas
Blog Entries: 2
Default Re: Cracking sound from amp - help

Quote:
Originally posted by Brit01
Hi guys,

Getting an occasional worrying crack/pop noise coming through my amp maybe once or twice an evening. Just on left channel.

It's a 1992 Carver TFM-55. One of the rails has been replaced with new power transistors (before I bought it).

Since then I've replaced most of the power caps, some differential transistors and some resistors.
Sounds very good with the new parts but bit worried now.

Maybe a sign of one of a power transistor going?
Or maybe an old mylar cap going?

Or some old Carbon Comp. resistors?
Does sound like maybe some solder/connection coming loose because of thermal expansion (possibly of the new output devices - could have been a bad solder job).

- keantoken
  Reply With Quote
Old 8th August 2009, 04:17 AM   #4
Brit01 is offline Brit01  United Kingdom
diyAudio Member
 
Join Date: Jul 2008
you may be right as it cracks loudly after warming up some 30 minutes.

Now the issue is where. Narrowed down to the right channel at least and I'm very familiar with the circuit as I've worked on it a great deal.

I'll be replacing some diodes and resistors in a few weeks so I'll give it a good look over.
  Reply With Quote
Old 8th August 2009, 09:58 AM   #5
diyAudio Member
 
sivan_and's Avatar
 
Join Date: Dec 2004
Location: B'lore/ Calicut India
Send a message via Yahoo to sivan_and
Check for any DC excursions at the output
__________________
SivanandBalan
  Reply With Quote
Old 8th August 2009, 01:13 PM   #6
djk is offline djk
diyAudio Member
 
djk's Avatar
 
Join Date: Feb 2001
Location: USA
"Or maybe an old mylar cap going?"

I suggest you replace the input coupling cap.

I've had the plating on the copperweld leads fail and it acts as you described.

Do not try an re-solder the original, replace it.

"Or some old Carbon Comp. resistors?"

They're carbon film type, and they can have the same copperweld lead issue. I would replace them too.

I would also replace the bias pot. If it goes open for an instant there will be a loud crack, and you could blow the amp and your speakers.
__________________
Candidates for the Darwin Award should not read this author.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Cracking/Static in Pre-Amp TheVille Solid State 2 17th April 2009 07:42 PM
Zenith K731 AM/FM radio audio random cracking sound in FM mode AC439 Tubes / Valves 15 20th February 2009 09:06 PM
A problem of cracking sound amp gaetan8888 Solid State 15 8th July 2007 07:41 PM
Cracking sound through speakers. magpietim Tubes / Valves 5 23rd October 2005 03:53 PM
cracking noise in P3a PetarLD Solid State 0 13th May 2004 04:03 AM


New To Site? Need Help?

All times are GMT. The time now is 01:00 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2